1. Field of the Invention
The invention concerns a compressed-gas gun (impulse gun) that utilizes the action of an expanding compressed gas, preferably compressed air, to fire single-piece projectile bodies, filled projectile bodies, or projectile bodies attached to an accessory device. The invention also relates to a method for removing damage using a compressed-gas gun.
2. Description of the Related Art
Shooting devices of a wide variety of designs are generally known. The different purposes for which shooting devices are used usually also require the use of different means of accelerating the projectile body and the use of different devices that are suitable for the purpose at hand. Examples of areas of application include:                the introduction of substances into places or locations that are exposed but poorly accessible or that pose a risk to the safety of personnel (firefighting, the triggering of an avalanche, etc.),        the shooting of auxiliary lines and rescue lines, first-aid packages, etc.,        the introduction of agents for protecting persons or property (tear gas, warfare agents, etc.).        
Both solid material (plastic, rubber, metals, etc.) and hollow bodies (filled with various types of solid, liquid, or gaseous charges, depending on the purpose of use) can be used as projectile bodies. In addition, special devices (rescue lines, auxiliary lines, etc.) can be attached to a projectile body, which serves as the carrier. Depending on the application, the projectile bodies can have different sizes, weights, shapes, or material compositions.
DE 2 227 114 A describes an arcade-type gun with a “bullet” barrel that can be connected with a source of compressed gas and with an additional blind barrel for a cartridge, which is connected by a gas channel with the loading end of the bullet barrel, so that a cartridge (blank cartridge) fired in the cartridge blind barrel becomes the source of compressed gas for the bullet barrel, and this compressed gas then shoots a bullet located at the loading end of the bullet barrel through the bullet barrel. The acceleration of the bullet is only moderate, but it is sufficient for the recreational purpose.
U.S. Pat. No. 3,369,609 A describes a compressed-gas gun for projecting fire extinguishing grenades, which consists of a gun barrel and a compressed-gas casing. The compressed-gas casing is divided into two pressure chambers by a stationary partition. In the fire-ready position, in which both chambers are filled with compressed gas, a valve stem, which is guided through the partition and has valves mounted on its ends, closes the breech with the front valve in the front pressure chamber, and closes a valve port that opens into the atmosphere with the rear valve in the rear pressure chamber. Both valves are in a state of equilibrium by virtue of the pressure of the compressed gas and of the valve stem that connects them, so that both valves are pressed tightly against their valve ports. To fire this compressed-gas gun, the compressed gas from the rear pressure chamber is discharged into the atmosphere, which causes the equilibrium to be altered in such a way that the front valve is opened by the valve stem, and the gas pressure present in the front pressure chamber propels the grenade through the gun barrel. The disadvantages of this previously known compressed-gas gun include especially its very expensive and complicated design.
U.S. Pat. No. 2,581,758 describes a compressed-gas gun for propelling harpoons or the like. It consists of a barrel with a compressed-gas casing, which is likewise divided into two chambers by a stationary partition. A slidable plunger, whose plunger rod is guided through the wall, is installed in the rear chamber (the working chamber), and in the front chamber (the compressed-gas chamber), a valve cap presses against the open end of the barrel; compressed gas introduced into the compressed-gas chamber and a compression spring, one end of which abuts against the plunger, provide for sufficient contact pressure. To fire this compressed-gas gun, compressed gas is admitted into the working chamber through a line, thereby pushing the plunger and opening the front valve by the plunger rod connected to the valve, and the harpoon is ejected by the compressed gas that is present.
Furthermore, methods and devices are known for the local destruction of compact materials, for example, slag incrustations, masonry residues, etc., in hot thermal installations and plants, such as heat exchangers, industrial furnaces, fuel firing plants, and metallurgical melting crucibles, in which an explosive is used, which is placed at the forward end of a lance, brought into the immediate vicinity of the material to be destroyed by supporting and moving the rear end of the lance through an opening of the hot thermal installation, and then ignited by means of an ignition device at a freely selectable time. However, devices of this type are unsuitable for use at greater distances from the compact materials.